Question

1/10

A population of Madagascar hissing cockroaches lives
in a woodpile. The cockroaches are eaten by lizards.
Because the lizards have small heads, the lizards are
unable to eat the very largest adult cockroaches, and
instead prey upon small and medium sized adults.
Over time, only the large headed lizards survive.

Disruptive

Stabilizing

Directional

Answer 1

The scenario you described illustrates a phenomenon of **directional selection**.

Here's the reasoning:

- **Directional selection** occurs when a population's traits shift in one direction. In this case, larger-headed lizards have a survival advantage because they can eat more of the available size range of cockroaches, thereby leading to a population shift towards larger head sizes in lizards.

- **Disruptive selection** would occur if two distinct phenotypes (for example, large and small) have a survival advantage over an intermediate phenotype, which is not the case here.

- **Stabilizing selection** would favor individuals with average traits, reducing variation, but the situation described leads to an increase in a specific trait (larger heads).

Thus, the correct answer is **directional selection**.